Basic performance of a continuous-flow isotope ratio mass spectrometer (Thermo Scientific GasBench II and Delta V Advantage) installed in the laboratory of evolution of earth environment of Kanazawa University is examined by multiple analyses of standard reference materials (NBS19, LSVEC, etc.). Internal precision of Delta V Advantage determined by 10 consecutive analyses of online reference CO₂ gas is 0.01 ‰ for both δ¹³C and δ¹⁸O values. Internal precision of GasBench II inlet system coupled to Delta V Advantage examined by four CO₂ gas aliquots, which is evolved by a reaction of 300 µg of NBS19 and anhydrous phosphoric acid, is 0.06 ‰and 0.08 ‰ for δ¹³C and δ¹⁸O, respectively. External precision of the system determined by 20 consecutive NBS19 analyses over 16 hours within the same day represents 0.02 ‰and 0.04 ‰ for δ¹³C and δ¹⁸O, respectively. A peak area of the first sample aliquot on a chromatogram detected on Delta V Advantage significantly correlates with amount of carbonate reacted (r = 0.99, p << 0.01). This positive correlation indicates that amount of carbonate within a given sample can be estimated from the chromatogram within an error of ±30 µg, which enable us to determine carbonate content of the bulk samples in at least better than 10 % precision.
守屋 et al. (Sun,) studied this question.